1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
2
3 /*
4 * Internal libbpf helpers.
5 *
6 * Copyright (c) 2019 Facebook
7 */
8
9 #ifndef __LIBBPF_LIBBPF_INTERNAL_H
10 #define __LIBBPF_LIBBPF_INTERNAL_H
11
12 #include <stdlib.h>
13 #include <limits.h>
14 #include <errno.h>
15 #include <linux/err.h>
16 #include "libbpf_legacy.h"
17 #include "relo_core.h"
18
19 /* make sure libbpf doesn't use kernel-only integer typedefs */
20 #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
21
22 /* prevent accidental re-addition of reallocarray() */
23 #pragma GCC poison reallocarray
24
25 #include "libbpf.h"
26 #include "btf.h"
27
28 #ifndef EM_BPF
29 #define EM_BPF 247
30 #endif
31
32 #ifndef R_BPF_64_64
33 #define R_BPF_64_64 1
34 #endif
35 #ifndef R_BPF_64_ABS64
36 #define R_BPF_64_ABS64 2
37 #endif
38 #ifndef R_BPF_64_ABS32
39 #define R_BPF_64_ABS32 3
40 #endif
41 #ifndef R_BPF_64_32
42 #define R_BPF_64_32 10
43 #endif
44
45 #ifndef SHT_LLVM_ADDRSIG
46 #define SHT_LLVM_ADDRSIG 0x6FFF4C03
47 #endif
48
49 /* if libelf is old and doesn't support mmap(), fall back to read() */
50 #ifndef ELF_C_READ_MMAP
51 #define ELF_C_READ_MMAP ELF_C_READ
52 #endif
53
54 /* Older libelf all end up in this expression, for both 32 and 64 bit */
55 #ifndef GELF_ST_VISIBILITY
56 #define GELF_ST_VISIBILITY(o) ((o) & 0x03)
57 #endif
58
59 #define BTF_INFO_ENC(kind, kind_flag, vlen) \
60 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
61 #define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
62 #define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
63 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
64 #define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
65 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
66 BTF_INT_ENC(encoding, bits_offset, bits)
67 #define BTF_MEMBER_ENC(name, type, bits_offset) (name), (type), (bits_offset)
68 #define BTF_PARAM_ENC(name, type) (name), (type)
69 #define BTF_VAR_SECINFO_ENC(type, offset, size) (type), (offset), (size)
70 #define BTF_TYPE_FLOAT_ENC(name, sz) \
71 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_FLOAT, 0, 0), sz)
72
73 #ifndef likely
74 #define likely(x) __builtin_expect(!!(x), 1)
75 #endif
76 #ifndef unlikely
77 #define unlikely(x) __builtin_expect(!!(x), 0)
78 #endif
79 #ifndef min
80 # define min(x, y) ((x) < (y) ? (x) : (y))
81 #endif
82 #ifndef max
83 # define max(x, y) ((x) < (y) ? (y) : (x))
84 #endif
85 #ifndef offsetofend
86 # define offsetofend(TYPE, FIELD) \
87 (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
88 #endif
89
90 /* Symbol versioning is different between static and shared library.
91 * Properly versioned symbols are needed for shared library, but
92 * only the symbol of the new version is needed for static library.
93 */
94 #ifdef SHARED
95 # define COMPAT_VERSION(internal_name, api_name, version) \
96 asm(".symver " #internal_name "," #api_name "@" #version);
97 # define DEFAULT_VERSION(internal_name, api_name, version) \
98 asm(".symver " #internal_name "," #api_name "@@" #version);
99 #else
100 # define COMPAT_VERSION(internal_name, api_name, version)
101 # define DEFAULT_VERSION(internal_name, api_name, version) \
102 extern typeof(internal_name) api_name \
103 __attribute__((alias(#internal_name)));
104 #endif
105
106 extern void libbpf_print(enum libbpf_print_level level,
107 const char *format, ...)
108 __attribute__((format(printf, 2, 3)));
109
110 #define __pr(level, fmt, ...) \
111 do { \
112 libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
113 } while (0)
114
115 #define pr_warn(fmt, ...) __pr(LIBBPF_WARN, fmt, ##__VA_ARGS__)
116 #define pr_info(fmt, ...) __pr(LIBBPF_INFO, fmt, ##__VA_ARGS__)
117 #define pr_debug(fmt, ...) __pr(LIBBPF_DEBUG, fmt, ##__VA_ARGS__)
118
119 #ifndef __has_builtin
120 #define __has_builtin(x) 0
121 #endif
122 /*
123 * Re-implement glibc's reallocarray() for libbpf internal-only use.
124 * reallocarray(), unfortunately, is not available in all versions of glibc,
125 * so requires extra feature detection and using reallocarray() stub from
126 * <tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates
127 * build of libbpf unnecessarily and is just a maintenance burden. Instead,
128 * it's trivial to implement libbpf-specific internal version and use it
129 * throughout libbpf.
130 */
libbpf_reallocarray(void * ptr,size_t nmemb,size_t size)131 static inline void *libbpf_reallocarray(void *ptr, size_t nmemb, size_t size)
132 {
133 size_t total;
134
135 #if __has_builtin(__builtin_mul_overflow)
136 if (unlikely(__builtin_mul_overflow(nmemb, size, &total)))
137 return NULL;
138 #else
139 if (size == 0 || nmemb > ULONG_MAX / size)
140 return NULL;
141 total = nmemb * size;
142 #endif
143 return realloc(ptr, total);
144 }
145
146 struct btf;
147 struct btf_type;
148
149 struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id);
150 const char *btf_kind_str(const struct btf_type *t);
151 const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
152
btf_func_linkage(const struct btf_type * t)153 static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
154 {
155 return (enum btf_func_linkage)(int)btf_vlen(t);
156 }
157
btf_type_info(int kind,int vlen,int kflag)158 static inline __u32 btf_type_info(int kind, int vlen, int kflag)
159 {
160 return (kflag << 31) | (kind << 24) | vlen;
161 }
162
163 enum map_def_parts {
164 MAP_DEF_MAP_TYPE = 0x001,
165 MAP_DEF_KEY_TYPE = 0x002,
166 MAP_DEF_KEY_SIZE = 0x004,
167 MAP_DEF_VALUE_TYPE = 0x008,
168 MAP_DEF_VALUE_SIZE = 0x010,
169 MAP_DEF_MAX_ENTRIES = 0x020,
170 MAP_DEF_MAP_FLAGS = 0x040,
171 MAP_DEF_NUMA_NODE = 0x080,
172 MAP_DEF_PINNING = 0x100,
173 MAP_DEF_INNER_MAP = 0x200,
174
175 MAP_DEF_ALL = 0x3ff, /* combination of all above */
176 };
177
178 struct btf_map_def {
179 enum map_def_parts parts;
180 __u32 map_type;
181 __u32 key_type_id;
182 __u32 key_size;
183 __u32 value_type_id;
184 __u32 value_size;
185 __u32 max_entries;
186 __u32 map_flags;
187 __u32 numa_node;
188 __u32 pinning;
189 };
190
191 int parse_btf_map_def(const char *map_name, struct btf *btf,
192 const struct btf_type *def_t, bool strict,
193 struct btf_map_def *map_def, struct btf_map_def *inner_def);
194
195 void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz,
196 size_t cur_cnt, size_t max_cnt, size_t add_cnt);
197 int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt);
198
libbpf_is_mem_zeroed(const char * p,ssize_t len)199 static inline bool libbpf_is_mem_zeroed(const char *p, ssize_t len)
200 {
201 while (len > 0) {
202 if (*p)
203 return false;
204 p++;
205 len--;
206 }
207 return true;
208 }
209
libbpf_validate_opts(const char * opts,size_t opts_sz,size_t user_sz,const char * type_name)210 static inline bool libbpf_validate_opts(const char *opts,
211 size_t opts_sz, size_t user_sz,
212 const char *type_name)
213 {
214 if (user_sz < sizeof(size_t)) {
215 pr_warn("%s size (%zu) is too small\n", type_name, user_sz);
216 return false;
217 }
218 if (!libbpf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
219 pr_warn("%s has non-zero extra bytes\n", type_name);
220 return false;
221 }
222 return true;
223 }
224
225 #define OPTS_VALID(opts, type) \
226 (!(opts) || libbpf_validate_opts((const char *)opts, \
227 offsetofend(struct type, \
228 type##__last_field), \
229 (opts)->sz, #type))
230 #define OPTS_HAS(opts, field) \
231 ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
232 #define OPTS_GET(opts, field, fallback_value) \
233 (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
234 #define OPTS_SET(opts, field, value) \
235 do { \
236 if (OPTS_HAS(opts, field)) \
237 (opts)->field = value; \
238 } while (0)
239
240 #define OPTS_ZEROED(opts, last_nonzero_field) \
241 ({ \
242 ssize_t __off = offsetofend(typeof(*(opts)), last_nonzero_field); \
243 !(opts) || libbpf_is_mem_zeroed((const void *)opts + __off, \
244 (opts)->sz - __off); \
245 })
246
247
248 int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);
249 int parse_cpu_mask_file(const char *fcpu, bool **mask, int *mask_sz);
250 int libbpf__load_raw_btf(const char *raw_types, size_t types_len,
251 const char *str_sec, size_t str_len);
252
253 struct bpf_prog_load_params {
254 enum bpf_prog_type prog_type;
255 enum bpf_attach_type expected_attach_type;
256 const char *name;
257 const struct bpf_insn *insns;
258 size_t insn_cnt;
259 const char *license;
260 __u32 kern_version;
261 __u32 attach_prog_fd;
262 __u32 attach_btf_obj_fd;
263 __u32 attach_btf_id;
264 __u32 prog_ifindex;
265 __u32 prog_btf_fd;
266 __u32 prog_flags;
267
268 __u32 func_info_rec_size;
269 const void *func_info;
270 __u32 func_info_cnt;
271
272 __u32 line_info_rec_size;
273 const void *line_info;
274 __u32 line_info_cnt;
275
276 __u32 log_level;
277 char *log_buf;
278 size_t log_buf_sz;
279 };
280
281 int libbpf__bpf_prog_load(const struct bpf_prog_load_params *load_attr);
282
283 int bpf_object__section_size(const struct bpf_object *obj, const char *name,
284 __u32 *size);
285 int bpf_object__variable_offset(const struct bpf_object *obj, const char *name,
286 __u32 *off);
287 struct btf *btf_get_from_fd(int btf_fd, struct btf *base_btf);
288 void btf_get_kernel_prefix_kind(enum bpf_attach_type attach_type,
289 const char **prefix, int *kind);
290
291 struct btf_ext_info {
292 /*
293 * info points to the individual info section (e.g. func_info and
294 * line_info) from the .BTF.ext. It does not include the __u32 rec_size.
295 */
296 void *info;
297 __u32 rec_size;
298 __u32 len;
299 };
300
301 #define for_each_btf_ext_sec(seg, sec) \
302 for (sec = (seg)->info; \
303 (void *)sec < (seg)->info + (seg)->len; \
304 sec = (void *)sec + sizeof(struct btf_ext_info_sec) + \
305 (seg)->rec_size * sec->num_info)
306
307 #define for_each_btf_ext_rec(seg, sec, i, rec) \
308 for (i = 0, rec = (void *)&(sec)->data; \
309 i < (sec)->num_info; \
310 i++, rec = (void *)rec + (seg)->rec_size)
311
312 /*
313 * The .BTF.ext ELF section layout defined as
314 * struct btf_ext_header
315 * func_info subsection
316 *
317 * The func_info subsection layout:
318 * record size for struct bpf_func_info in the func_info subsection
319 * struct btf_sec_func_info for section #1
320 * a list of bpf_func_info records for section #1
321 * where struct bpf_func_info mimics one in include/uapi/linux/bpf.h
322 * but may not be identical
323 * struct btf_sec_func_info for section #2
324 * a list of bpf_func_info records for section #2
325 * ......
326 *
327 * Note that the bpf_func_info record size in .BTF.ext may not
328 * be the same as the one defined in include/uapi/linux/bpf.h.
329 * The loader should ensure that record_size meets minimum
330 * requirement and pass the record as is to the kernel. The
331 * kernel will handle the func_info properly based on its contents.
332 */
333 struct btf_ext_header {
334 __u16 magic;
335 __u8 version;
336 __u8 flags;
337 __u32 hdr_len;
338
339 /* All offsets are in bytes relative to the end of this header */
340 __u32 func_info_off;
341 __u32 func_info_len;
342 __u32 line_info_off;
343 __u32 line_info_len;
344
345 /* optional part of .BTF.ext header */
346 __u32 core_relo_off;
347 __u32 core_relo_len;
348 };
349
350 struct btf_ext {
351 union {
352 struct btf_ext_header *hdr;
353 void *data;
354 };
355 struct btf_ext_info func_info;
356 struct btf_ext_info line_info;
357 struct btf_ext_info core_relo_info;
358 __u32 data_size;
359 };
360
361 struct btf_ext_info_sec {
362 __u32 sec_name_off;
363 __u32 num_info;
364 /* Followed by num_info * record_size number of bytes */
365 __u8 data[];
366 };
367
368 /* The minimum bpf_func_info checked by the loader */
369 struct bpf_func_info_min {
370 __u32 insn_off;
371 __u32 type_id;
372 };
373
374 /* The minimum bpf_line_info checked by the loader */
375 struct bpf_line_info_min {
376 __u32 insn_off;
377 __u32 file_name_off;
378 __u32 line_off;
379 __u32 line_col;
380 };
381
382
383 typedef int (*type_id_visit_fn)(__u32 *type_id, void *ctx);
384 typedef int (*str_off_visit_fn)(__u32 *str_off, void *ctx);
385 int btf_type_visit_type_ids(struct btf_type *t, type_id_visit_fn visit, void *ctx);
386 int btf_type_visit_str_offs(struct btf_type *t, str_off_visit_fn visit, void *ctx);
387 int btf_ext_visit_type_ids(struct btf_ext *btf_ext, type_id_visit_fn visit, void *ctx);
388 int btf_ext_visit_str_offs(struct btf_ext *btf_ext, str_off_visit_fn visit, void *ctx);
389
390 extern enum libbpf_strict_mode libbpf_mode;
391
392 /* handle direct returned errors */
libbpf_err(int ret)393 static inline int libbpf_err(int ret)
394 {
395 if (ret < 0)
396 errno = -ret;
397 return ret;
398 }
399
400 /* handle errno-based (e.g., syscall or libc) errors according to libbpf's
401 * strict mode settings
402 */
libbpf_err_errno(int ret)403 static inline int libbpf_err_errno(int ret)
404 {
405 if (libbpf_mode & LIBBPF_STRICT_DIRECT_ERRS)
406 /* errno is already assumed to be set on error */
407 return ret < 0 ? -errno : ret;
408
409 /* legacy: on error return -1 directly and don't touch errno */
410 return ret;
411 }
412
413 /* handle error for pointer-returning APIs, err is assumed to be < 0 always */
libbpf_err_ptr(int err)414 static inline void *libbpf_err_ptr(int err)
415 {
416 /* set errno on error, this doesn't break anything */
417 errno = -err;
418
419 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
420 return NULL;
421
422 /* legacy: encode err as ptr */
423 return ERR_PTR(err);
424 }
425
426 /* handle pointer-returning APIs' error handling */
libbpf_ptr(void * ret)427 static inline void *libbpf_ptr(void *ret)
428 {
429 /* set errno on error, this doesn't break anything */
430 if (IS_ERR(ret))
431 errno = -PTR_ERR(ret);
432
433 if (libbpf_mode & LIBBPF_STRICT_CLEAN_PTRS)
434 return IS_ERR(ret) ? NULL : ret;
435
436 /* legacy: pass-through original pointer */
437 return ret;
438 }
439
str_is_empty(const char * s)440 static inline bool str_is_empty(const char *s)
441 {
442 return !s || !s[0];
443 }
444
is_ldimm64_insn(struct bpf_insn * insn)445 static inline bool is_ldimm64_insn(struct bpf_insn *insn)
446 {
447 return insn->code == (BPF_LD | BPF_IMM | BPF_DW);
448 }
449
450 #endif /* __LIBBPF_LIBBPF_INTERNAL_H */
451
